A West Australian tax scheme ­promoter,
Greg Dunn
, was found guilty of a tax conspiracy in criminal proceedings held in the Supreme Court that have entangled two of the state’s most prominent mining entrepreneurs.

The jury found Dunn guilty on Friday.

Accountant Deborah Grace was cleared of the same charge.

The jury is yet to make a decision about Ausdrill managing director
Ron ­Sayers
and Barminco founder
Peter Bartlett
, who were also charged with conspiring to cause loss to the federal government.

All four pleaded not guilty to a charge that carries a possible prison term of up to 10 years.

The lengthy trial concluded ­earlier in the week.

Dunn, who represented himself in the trial, was remanded in ­custody. He is expected to appeal.

Prosecutors alleged that in 1999, Mr Bartlett and Mr Sayers entered into a tax minimisation plan for their family trusts known as an “appointor scheme" and were aided by the other accused men. The four allegedly conspired to create a false transaction to preserve the integrity of legal advice underpinning the scheme.